I. Field of the invention
The present invention relates to the field of engine control. More specifically, it relates to a strategy for opening the intake throttle of an internal combustion engine.
This invention finds a favored, although non-exclusive, application in normally-aspirated spark-ignition gasoline engines, but turbocharged diesel engines can also benefit from the proposed strategy.
II. Description of Related Art
Under full load acceleration, the throttle pedal is fully depressed. The computer sends the “wide open throttle” information to the motorized throttle valve body assembly, and the throttle valve is opened wide throughout the speed range. The cross section opened up by opening the throttle wide is designed not to restrict the air supply to the engine when the air supply is entering at its maximum flowrate. The size of the opening is therefore calculated to meet maximum flowrate requirements, that is to say to provide maximum power. Thus, the opening in the throttle valve body assembly is often too great, and the throttle valve body assembly is therefore oversized.
Opening the throttle wider than just the amount needed has no positive effect on engine behavior or performance but detracts from the pleasure of driving the vehicle by needlessly increasing the level of engine noise. Indeed, it has been found that some engine noise, identified as “induction noise” is directly associated with the opening of the throttle.
Publication JP 200129571 discloses a reduction in engine noise by modifying the passage cross section for air through the induction circuit. The system described does actually make it possible to limit the noise level under certain circumstances but takes no account of the true engine operating conditions.